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From:   "Jason A. Donenfeld" <Jason@zx2c4.com>
To:     linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc:     "Jason A. Donenfeld" <Jason@zx2c4.com>,
        Eric B Munson <emunson@akamai.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: [PATCH] mm: do not show ?? for VM_LOCKONFAULT pages
Date:   Mon,  5 Dec 2022 18:30:07 +0100
Message-Id: <20221205173007.580210-1-Jason@zx2c4.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

When VM_LOCKONFAULT was added, /proc/PID/smaps wasn't hooked up to it,
so looking at /proc/PID/smaps, it shows '??' instead of something
intelligable. This can be reached by userspace by simply calling
`mlock2(..., MLOCK_ONFAULT);`.

Fix this by adding "lf" to denote VM_LOCKONFAULT.

Cc: Eric B Munson <emunson@akamai.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Fixes: de60f5f10c58 ("mm: introduce VM_LOCKONFAULT")
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
 fs/proc/task_mmu.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 8a74cdcc9af0..60851e96530b 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -667,6 +667,7 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
 		[ilog2(VM_RAND_READ)]	= "rr",
 		[ilog2(VM_DONTCOPY)]	= "dc",
 		[ilog2(VM_DONTEXPAND)]	= "de",
+		[ilog2(VM_LOCKONFAULT)]	= "lf",
 		[ilog2(VM_ACCOUNT)]	= "ac",
 		[ilog2(VM_NORESERVE)]	= "nr",
 		[ilog2(VM_HUGETLB)]	= "ht",
-- 
2.38.1